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Ungvari A, Gulej R, Csik B, Mukli P, Negri S, Tarantini S, Yabluchanskiy A, Benyo Z, Csiszar A, Ungvari Z. The Role of Methionine-Rich Diet in Unhealthy Cerebrovascular and Brain Aging: Mechanisms and Implications for Cognitive Impairment. Nutrients 2023; 15:4662. [PMID: 37960316 PMCID: PMC10650229 DOI: 10.3390/nu15214662] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 10/28/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023] Open
Abstract
As aging societies in the western world face a growing prevalence of vascular cognitive impairment and Alzheimer's disease (AD), understanding their underlying causes and associated risk factors becomes increasingly critical. A salient concern in the western dietary context is the high consumption of methionine-rich foods such as red meat. The present review delves into the impact of this methionine-heavy diet and the resultant hyperhomocysteinemia on accelerated cerebrovascular and brain aging, emphasizing their potential roles in cognitive impairment. Through a comprehensive exploration of existing evidence, a link between high methionine intake and hyperhomocysteinemia and oxidative stress, mitochondrial dysfunction, inflammation, and accelerated epigenetic aging is drawn. Moreover, the microvascular determinants of cognitive deterioration, including endothelial dysfunction, reduced cerebral blood flow, microvascular rarefaction, impaired neurovascular coupling, and blood-brain barrier (BBB) disruption, are explored. The mechanisms by which excessive methionine consumption and hyperhomocysteinemia might drive cerebromicrovascular and brain aging processes are elucidated. By presenting an intricate understanding of the relationships among methionine-rich diets, hyperhomocysteinemia, cerebrovascular and brain aging, and cognitive impairment, avenues for future research and potential therapeutic interventions are suggested.
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Affiliation(s)
- Anna Ungvari
- Department of Public Health, Semmelweis University, 1089 Budapest, Hungary
| | - Rafal Gulej
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Boglarka Csik
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Public Health, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
| | - Peter Mukli
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Public Health, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
| | - Sharon Negri
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Stefano Tarantini
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Public Health, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
- Stephenson Cancer Center, University of Oklahoma, Oklahoma City, OK 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Andriy Yabluchanskiy
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Public Health, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
- Stephenson Cancer Center, University of Oklahoma, Oklahoma City, OK 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Zoltan Benyo
- Institute of Translational Medicine, Semmelweis University, 1094 Budapest, Hungary;
- Cerebrovascular and Neurocognitive Disorders Research Group, Eötvös Loránd Research Network, Semmelweis University, 1094 Budapest, Hungary
| | - Anna Csiszar
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Stephenson Cancer Center, University of Oklahoma, Oklahoma City, OK 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Translational Medicine, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
| | - Zoltan Ungvari
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (R.G.); (B.C.); (P.M.); (S.N.); (S.T.); (A.Y.); (A.C.); (Z.U.)
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Department of Public Health, Doctoral School of Basic and Translational Medicine, Semmelweis University, 1089 Budapest, Hungary
- Stephenson Cancer Center, University of Oklahoma, Oklahoma City, OK 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Demchenko IT, Suliman HB, Zhilyaey SY, Alekseeva OS, Platonova TF, Makowski MS, Piantadosi CA, Gasier HG. GAT inhibition preserves cerebral blood flow and reduces oxidant damage to mitochondria in rodents exposed to extreme hyperbaric oxygen. Front Mol Neurosci 2023; 15:1062410. [PMID: 36704328 PMCID: PMC9871636 DOI: 10.3389/fnmol.2022.1062410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 12/22/2022] [Indexed: 01/11/2023] Open
Abstract
Oxygen breathing at elevated partial pressures (PO2's) at or more than 3 atmospheres absolute (ATA) causes a reduction in brain γ-aminobutyric acid (GABA) levels that impacts the development of central nervous system oxygen toxicity (CNS-OT). Drugs that increase brain GABA content delay the onset of CNS-OT, but it is unknown if oxidant damage is lessened because brain tissue PO2 remains elevated during hyperbaric oxygen (HBO2) exposures. Experiments were performed in rats and mice to measure brain GABA levels with or without GABA transporter inhibitors (GATs) and its influence on cerebral blood flow, oxidant damage, and aspects of mitochondrial quality control signaling (mitophagy and biogenesis). In rats pretreated with tiagabine (GAT1 inhibitor), the tachycardia, secondary rise in mean arterial blood pressure, and cerebral hyperemia were prevented during HBO2 at 5 and 6 ATA. Tiagabine and the nonselective GAT inhibitor nipecotic acid similarly extended HBO2 seizure latencies. In mice pretreated with tiagabine and exposed to HBO2 at 5 ATA, nuclear and mitochondrial DNA oxidation and astrocytosis was attenuated in the cerebellum and hippocampus. Less oxidant injury in these regions was accompanied by reduced conjugated microtubule-associated protein 1A/1B-light chain 3 (LC3-II), an index of mitophagy, and phosphorylated cAMP response element binding protein (pCREB), an initiator of mitochondrial biogenesis. We conclude that GABA prevents cerebral hyperemia and delays neuroexcitation under extreme HBO2, limiting oxidant damage in the cerebellum and hippocampus, and likely lowering mitophagy flux and initiation of pCREB-initiated mitochondrial biogenesis.
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Affiliation(s)
- Ivan T. Demchenko
- The Duke Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, United States,Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Hagir B. Suliman
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Sergey Y. Zhilyaey
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Olga S. Alekseeva
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Tatyana F. Platonova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Matthew S. Makowski
- The Duke Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, United States
| | - Claude A. Piantadosi
- The Duke Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, United States
| | - Heath G. Gasier
- The Duke Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, United States,*Correspondence: Heath G. Gasier, ✉
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Hirunpattarasilp C, Barkaway A, Davis H, Pfeiffer T, Sethi H, Attwell D. Hyperoxia evokes pericyte-mediated capillary constriction. J Cereb Blood Flow Metab 2022; 42:2032-2047. [PMID: 35786054 PMCID: PMC9580167 DOI: 10.1177/0271678x221111598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Oxygen supplementation is regularly prescribed to patients to treat or prevent hypoxia. However, excess oxygenation can lead to reduced cerebral blood flow (CBF) in healthy subjects and worsen the neurological outcome of critically ill patients. Most studies on the vascular effects of hyperoxia focus on arteries but there is no research on the effects on cerebral capillary pericytes, which are major regulators of CBF. Here, we used bright-field imaging of cerebral capillaries and modeling of CBF to show that hyperoxia (95% superfused O2) led to an increase in intracellular calcium level in pericytes and a significant capillary constriction, sufficient to cause an estimated 25% decrease in CBF. Although hyperoxia is reported to cause vascular smooth muscle cell contraction via generation of reactive oxygen species (ROS), endothelin-1 and 20-HETE, we found that increased cytosolic and mitochondrial ROS levels and endothelin release were not involved in the pericyte-mediated capillary constriction. However, a 20-HETE synthesis blocker greatly reduced the hyperoxia-evoked capillary constriction. Our findings establish pericytes as regulators of CBF in hyperoxia and 20-HETE synthesis as an oxygen sensor in CBF regulation. The results also provide a mechanism by which clinically administered oxygen can lead to a worse neurological outcome.
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Affiliation(s)
- Chanawee Hirunpattarasilp
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK.,Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Anna Barkaway
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK.,Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Harvey Davis
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK.,Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Thomas Pfeiffer
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK
| | - Huma Sethi
- Division of Neurosurgery, UCL Queen Square Institute of Neurology, Queen Square, London, UK
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK
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4
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Dean JB, Stavitzski NM. The O2-sensitive brain stem, hyperoxic hyperventilation, and CNS oxygen toxicity. Front Physiol 2022; 13:921470. [PMID: 35957982 PMCID: PMC9360621 DOI: 10.3389/fphys.2022.921470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Central nervous system oxygen toxicity (CNS-OT) is a complex disorder that presents, initially, as a sequence of cardio-respiratory abnormalities and nonconvulsive signs and symptoms (S/Sx) of brain stem origin that culminate in generalized seizures, loss of consciousness, and postictal cardiogenic pulmonary edema. The risk of CNS-OT and its antecedent “early toxic indications” are what limits the use of hyperbaric oxygen (HBO2) in hyperbaric and undersea medicine. The purpose of this review is to illustrate, based on animal research, how the temporal pattern of abnormal brain stem responses that precedes an “oxtox hit” provides researchers a window into the early neurological events underlying seizure genesis. Specifically, we focus on the phenomenon of hyperoxic hyperventilation, and the medullary neurons presumed to contribute in large part to this paradoxical respiratory response; neurons in the caudal Solitary complex (cSC) of the dorsomedial medulla, including putative CO2 chemoreceptor neurons. The electrophysiological and redox properties of O2-/CO2-sensitive cSC neurons identified in rat brain slice experiments are summarized. Additionally, evidence is summarized that supports the working hypothesis that seizure genesis originates in subcortical areas and involves cardio-respiratory centers and cranial nerve nuclei in the hind brain (brainstem and cerebellum) based on, respectively, the complex temporal pattern of abnormal cardio-respiratory responses and various nonconvulsive S/Sx that precede seizures during exposure to HBO2.
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5
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Lansdell TA, Chambers LC, Dorrance AM. Endothelial Cells and the Cerebral Circulation. Compr Physiol 2022; 12:3449-3508. [PMID: 35766836 DOI: 10.1002/cphy.c210015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Endothelial cells form the innermost layer of all blood vessels and are the only vascular component that remains throughout all vascular segments. The cerebral vasculature has several unique properties not found in the peripheral circulation; this requires that the cerebral endothelium be considered as a unique entity. Cerebral endothelial cells perform several functions vital for brain health. The cerebral vasculature is responsible for protecting the brain from external threats carried in the blood. The endothelial cells are central to this requirement as they form the basis of the blood-brain barrier. The endothelium also regulates fibrinolysis, thrombosis, platelet activation, vascular permeability, metabolism, catabolism, inflammation, and white cell trafficking. Endothelial cells regulate the changes in vascular structure caused by angiogenesis and artery remodeling. Further, the endothelium contributes to vascular tone, allowing proper perfusion of the brain which has high energy demands and no energy stores. In this article, we discuss the basic anatomy and physiology of the cerebral endothelium. Where appropriate, we discuss the detrimental effects of high blood pressure on the cerebral endothelium and the contribution of cerebrovascular disease endothelial dysfunction and dementia. © 2022 American Physiological Society. Compr Physiol 12:3449-3508, 2022.
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Affiliation(s)
- Theresa A Lansdell
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
| | - Laura C Chambers
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
| | - Anne M Dorrance
- Department of Pharmacology and Toxicology, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, 48824, USA
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Choi J, Kwon HJ, Seoh JY, Han PL. Hyperoxygenation Ameliorates Stress-induced Neuronal and Behavioral Deficits. Exp Neurobiol 2021; 30:415-429. [PMID: 34983882 PMCID: PMC8752323 DOI: 10.5607/en21029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 11/23/2022] Open
Abstract
Hyperoxygenation therapy remediates neuronal injury and improves cognitive function in various animal models. In the present study, the optimal conditions for hyperoxygenation treatment of stress-induced maladaptive changes were investigated. Mice exposed to chronic restraint stress (CRST) produce persistent adaptive changes in genomic responses and exhibit depressive-like behaviors. Hyperoxygenation treatment with 100% O2 (HO2) at 2.0 atmospheres absolute (ATA) for 1 h daily for 14 days in CRST mice produces an antidepressive effect similar to that of the antidepressant imipramine. In contrast, HO2 treatment at 2.0 ATA for 1 h daily for shorter duration (3, 5, or 7 days), HO2 treatment at 1.5 ATA for 1 h daily for 14 days, or hyperbaric air treatment at 2.0 ATA (42% O2) for 1 h daily for 14 days is ineffective or less effective, indicating that repeated sufficient hyperoxygenation conditions are required to reverse stress-induced maladaptive changes. HO2 treatment at 2.0 ATA for 14 days restores stress-induced reductions in levels of mitochondrial copy number, stress-induced attenuation of synaptophysin-stained density of axon terminals and MAP-2-staining dendritic processes of pyramidal neurons in the hippocampus, and stress-induced reduced hippocampal neurogenesis. These results suggest that HO2 treatment at 2.0 ATA for 14 days is effective to ameliorate stress-induced neuronal and behavioral deficits.
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Affiliation(s)
- Juli Choi
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul 03760, Korea
| | - Hye-Jin Kwon
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul 03760, Korea
| | - Ju-Young Seoh
- Department of Microbiology, College of Medicine, Ewha Womans University, Seoul 07985, Korea.,Central Research Laboratory, GI Biome, Inc., Seongnam 13201, Korea
| | - Pyung-Lim Han
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul 03760, Korea
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7
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Balasubramanian P, Delfavero J, Nyul-Toth A, Tarantini A, Gulej R, Tarantini S. Integrative Role of Hyperbaric Oxygen Therapy on Healthspan, Age-Related Vascular Cognitive Impairment, and Dementia. FRONTIERS IN AGING 2021; 2:678543. [PMID: 35821996 PMCID: PMC9261405 DOI: 10.3389/fragi.2021.678543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 09/09/2021] [Indexed: 12/17/2022]
Abstract
Growing life expectancy will contribute to the on-going shift towards a world population increasingly comprised of elderly individuals. This demographic shift is associated with a rising prevalence of age-related diseases, among all age-related pathologies it has become crucial to understand the age-associated cognitive changes that remain a major risk factor for the development of vascular cognitive impairment and dementia (VCID). Furthermore, age-related Alzheimer's disease and other neurogenerative diseases with vascular etiology are the most prominent contributing factors for the loss of cognitive function observed in aging. Hyperbaric Oxygen Therapy (HBOT) achieves physiologic effects by increasing oxygen tension (PO2), raising oxygen tissue levels, decreasing intracranial pressure and relieving cerebral edema. Many of the beneficial effects of HBOT exert their protective effects at the level of the microcirculation. Furthermore, the microcirculation's exquisite pervasive presence across every tissue in the body, renders it uniquely able to influence the local environment of most tissues and organs, including the brain. As such, treatments aimed at restoring aging-induced functional and structural alterations of the cerebral microcirculation may potentially contribute to the amelioration of a range of age-related pathologies including vascular cognitive impairment, Alzheimer's disease, and vascular dementias. Despite the presented evidence, the efficacy and safety of HBOT for the treatment of age-related vascular cognitive impairment and dementia remains understudied. The present review aims to examine the existing evidence indicative of a potential therapeutic role for HBOT-induced hyperoxia against age-related cerebromicrovascular pathologies contributing to cognitive impairment, dementia and decreased healthspan in the elderly.
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Affiliation(s)
- Priya Balasubramanian
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Jordan Delfavero
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Adam Nyul-Toth
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- International Training Program in Geroscience, Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
| | - Amber Tarantini
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Rafal Gulej
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Stefano Tarantini
- Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
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8
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Nizari S, Basalay M, Chapman P, Korte N, Korsak A, Christie IN, Theparambil SM, Davidson SM, Reimann F, Trapp S, Yellon DM, Gourine AV. Glucagon-like peptide-1 (GLP-1) receptor activation dilates cerebral arterioles, increases cerebral blood flow, and mediates remote (pre)conditioning neuroprotection against ischaemic stroke. Basic Res Cardiol 2021; 116:32. [PMID: 33942194 PMCID: PMC8093159 DOI: 10.1007/s00395-021-00873-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 04/22/2021] [Indexed: 12/12/2022]
Abstract
Stroke remains one of the most common causes of death and disability worldwide. Several preclinical studies demonstrated that the brain can be effectively protected against ischaemic stroke by two seemingly distinct treatments: remote ischaemic conditioning (RIC), involving cycles of ischaemia/reperfusion applied to a peripheral organ or tissue, or by systemic administration of glucagon-like-peptide-1 (GLP-1) receptor (GLP-1R) agonists. The mechanisms underlying RIC- and GLP-1-induced neuroprotection are not completely understood. In this study, we tested the hypothesis that GLP-1 mediates neuroprotection induced by RIC and investigated the effect of GLP-1R activation on cerebral blood vessels, as a potential mechanism of GLP-1-induced protection against ischaemic stroke. A rat model of ischaemic stroke (90 min of middle cerebral artery occlusion followed by 24-h reperfusion) was used. RIC was induced by 4 cycles of 5 min left hind limb ischaemia interleaved with 5-min reperfusion periods. RIC markedly (by ~ 80%) reduced the cerebral infarct size and improved the neurological score. The neuroprotection established by RIC was abolished by systemic blockade of GLP-1R with a specific antagonist Exendin(9-39). In the cerebral cortex of GLP-1R reporter mice, ~ 70% of cortical arterioles displayed GLP-1R expression. In acute brain slices of the rat cerebral cortex, activation of GLP-1R with an agonist Exendin-4 had a strong dilatory effect on cortical arterioles and effectively reversed arteriolar constrictions induced by metabolite lactate or oxygen and glucose deprivation, as an ex vivo model of ischaemic stroke. In anaesthetised rats, Exendin-4 induced lasting increases in brain tissue PO2, indicative of increased cerebral blood flow. These results demonstrate that neuroprotection against ischaemic stroke established by remote ischaemic conditioning is mediated by a mechanism involving GLP-1R signalling. Potent dilatory effect of GLP-1R activation on cortical arterioles suggests that the neuroprotection in this model is mediated via modulation of cerebral blood flow and improved brain perfusion.
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Affiliation(s)
- Shereen Nizari
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Marina Basalay
- The Hatter Cardiovascular Institute, University College London, London, WC1E 6HX, UK
| | - Philippa Chapman
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Nils Korte
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Alla Korsak
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Isabel N Christie
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Shefeeq M Theparambil
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Sean M Davidson
- The Hatter Cardiovascular Institute, University College London, London, WC1E 6HX, UK
| | - Frank Reimann
- Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Stefan Trapp
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Derek M Yellon
- The Hatter Cardiovascular Institute, University College London, London, WC1E 6HX, UK
| | - Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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9
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Balasubramanian P, Kiss T, Tarantini S, Nyúl-Tóth Á, Ahire C, Yabluchanskiy A, Csipo T, Lipecz A, Tabak A, Institoris A, Csiszar A, Ungvari Z. Obesity-induced cognitive impairment in older adults: a microvascular perspective. Am J Physiol Heart Circ Physiol 2021; 320:H740-H761. [PMID: 33337961 PMCID: PMC8091942 DOI: 10.1152/ajpheart.00736.2020] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Over two-thirds of individuals aged 65 and older are obese or overweight in the United States. Epidemiological data show an association between the degree of adiposity and cognitive dysfunction in the elderly. In this review, the pathophysiological roles of microvascular mechanisms, including impaired endothelial function and neurovascular coupling responses, microvascular rarefaction, and blood-brain barrier disruption in the genesis of cognitive impairment in geriatric obesity are considered. The potential contribution of adipose-derived factors and fundamental cellular and molecular mechanisms of senescence to exacerbated obesity-induced cerebromicrovascular impairment and cognitive decline in aging are discussed.
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Affiliation(s)
- Priya Balasubramanian
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Tamas Kiss
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2International Training Program in Geroscience, Theoretical Medicine Doctoral School, Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Stefano Tarantini
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,3International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary,4Department of Health Promotion Sciences, the Hudson College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Ádám Nyúl-Tóth
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,5International Training Program in Geroscience, Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Chetan Ahire
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Andriy Yabluchanskiy
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Tamas Csipo
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,3International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary,6International Training Program in Geroscience, Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Agnes Lipecz
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,3International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary
| | - Adam Tabak
- 3International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary,7Department of Internal Medicine and Oncology, Faculty of Medicine, Semmelweis University, Budapest, Hungary,8Department of Epidemiology and Public Health, University College London, London, United Kingdom
| | - Adam Institoris
- 9Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Anna Csiszar
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2International Training Program in Geroscience, Theoretical Medicine Doctoral School, Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Zoltan Ungvari
- 1Vascular Cognitive Impairment and Neurodegeneration Program, Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2International Training Program in Geroscience, Theoretical Medicine Doctoral School, Departments of Medical Physics and Informatics & Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary,3International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine, Department of Public Health, Semmelweis University, Budapest, Hungary,4Department of Health Promotion Sciences, the Hudson College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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10
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Lee K, Bohnert S, Vair C, Mikler J, Dunn JF. Cerebral blood flow and oxygenation in rat brain after soman exposure. Toxicol Lett 2021; 336:50-56. [PMID: 33147512 DOI: 10.1016/j.toxlet.2020.10.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 08/14/2020] [Accepted: 10/20/2020] [Indexed: 11/28/2022]
Abstract
Nerve agent exposure can cause debilitating neurological damage even with treatment. Currently accepted treatments involve attenuating the cholinergic crisis and seizure onset but do not focus directly on neuroprotection. Hence, there is a need for improved treatments to reduce neurological deficits. It is important to understand the pathophysiology of nerve agent mediated injury in order to identify effective treatment targets. Nerve agent-induced seizures are believed to be the main contributor to the neuropathology. Recently seizures have been shown to cause vascular changes that may actually attenuate neurological damage. This study evaluated the effect of soman-induced convulsive seizures on the relationship between CNS oxygen consumption and supply. To simultaneously assess changes in oxygenation and perfusion, rats were implanted with permanently fixed fiber-optic tissue oxygen sensing probes in the motor cortex and imaged with continuous arterial spin labelling MRI to measure cerebral blood flow. Baseline tissue oxygen tension (ptO2) and cerebral blood flow (CBF) were measured in isoflurane anaesthetized rats at least one day prior to soman or saline exposure. Rats were pretreated with HI-6 dimethansulfonate and atropine methyl nitrate (125 mg/kg and 20 mg/kg; intraperitoneal) followed by a convulsive dose of soman (90 μg/kg; subcutaneous) or equal volume of saline. Three additional treatments of HI-6/AMN were administered to improve survival. At 1.5 -hs after exposure, ptO2 and cerebral blood flow measurements were conducted. There was a significant decrease in CBF 1.5 -hs following soman exposure but no change in ptO2 was found. When we correlated ptO2 and CBF, for a given ptO2, there was lower CBF following soman exposure. This may indicate metabolism is inhibited, possibly because of mitochondrial impairment, therefore reducing oxygen demand. These data show hypoperfusion in brain following soman exposure which would be expected to contribute to soman-related neuropathology.
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Affiliation(s)
- Kevin Lee
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sara Bohnert
- Defence Research and Development Canada- Suffield Research Centre, Department of National Defence, Alberta, Canada
| | - Cory Vair
- Defence Research and Development Canada- Suffield Research Centre, Department of National Defence, Alberta, Canada
| | - John Mikler
- Defence Research and Development Canada- Suffield Research Centre, Department of National Defence, Alberta, Canada
| | - Jeff F Dunn
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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11
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Cerebrospinal fluid oxygen optimisation for rescue of metabolically challenged in vitro cortical brain tissue. IBRO Rep 2020; 9:302-309. [PMID: 33235940 PMCID: PMC7670121 DOI: 10.1016/j.ibror.2020.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 10/30/2020] [Indexed: 11/23/2022] Open
Abstract
Hypoxic-ischaemic brain injury is a major cause of morbidity and mortality internationally. Using an in vitro isolated cortex model, this study investigated the optimal cerebrospinal fluid oxygenation parameters for rescuing metabolically challenged cortical tissue. In particular, we asked whether maximizing oxygen content with oxygen nanobubbles could support improved tissue recovery. Mouse cortical slices were metabolically starved, followed by recovery in artificial cerebrospinal fluid (aCSF) containing different levels of dissolved oxygen ranging from mean(SD) 2(0.5) to 39(1.0) mg/L; with and without oxygen nanobubbles. Tissue recovery was assessed by quantifying and comparing the amplitude, length, high frequency content and event frequency of seizure-like events generated in no-magnesium aCSF at the beginning and end of the protocol. In general, there was improved recovery with increasing oxygen content up to 25-34 mg/L. The outcome of slices recovered in nanobubbled aCSF was no different to conventionally oxygenated slices with similar dissolved oxygen content. Dissolved oxygen content above 34 mg/L afforded no additional benefit. In conclusion, aCSF dissolved oxygen content of approximately 30 mg/L is optimal for cortical tissue recovery from metabolic starvation, which is easily achievable using conventional oxygenation methods. Oxygen in the form of nanobubbles does not appear to be readily available for tissue oxidative processes in this model.
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12
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Dean JB. The beneficial O 2 paradox: hyperoxia-enhanced neurocognition and vigilance during reduction in global cerebral blood flow. J Physiol 2020; 598:3821-3822. [PMID: 32697328 DOI: 10.1113/jp280326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Jay B Dean
- Department of Molecular Pharmacology and Physiology, USF Hyperbaric Biomedical Research Laboratory, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Boulevard, MDC 8, Tampa, FL, 33612, USA
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13
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Ciarlone GE, Hinojo CM, Stavitzski NM, Dean JB. CNS function and dysfunction during exposure to hyperbaric oxygen in operational and clinical settings. Redox Biol 2019; 27:101159. [PMID: 30902504 PMCID: PMC6859559 DOI: 10.1016/j.redox.2019.101159] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/20/2019] [Accepted: 03/01/2019] [Indexed: 12/26/2022] Open
Abstract
Hyperbaric oxygen (HBO2) is breathed during hyperbaric oxygen therapy and during certain undersea pursuits in diving and submarine operations. What limits exposure to HBO2 in these situations is the acute onset of central nervous system oxygen toxicity (CNS-OT) following a latent period of safe oxygen breathing. CNS-OT presents as various non-convulsive signs and symptoms, many of which appear to be of brainstem origin involving cranial nerve nuclei and autonomic and cardiorespiratory centers, which ultimately spread to higher cortical centers and terminate as generalized tonic-clonic seizures. The initial safe latent period makes the use of HBO2 practical in hyperbaric and undersea medicine; however, the latent period is highly variable between individuals and within the same individual on different days, making it difficult to predict onset of toxic indications. Consequently, currently accepted guidelines for safe HBO2 exposure are highly conservative. This review examines the disorder of CNS-OT and summarizes current ideas on its underlying pathophysiology, including specific areas of the CNS and fundamental neural and redox signaling mechanisms that are thought to be involved in seizure genesis and propagation. In addition, conditions that accelerate the onset of seizures are discussed, as are current mitigation strategies under investigation for neuroprotection against redox stress while breathing HBO2 that extend the latent period, thus enabling safer and longer exposures for diving and medical therapies.
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Affiliation(s)
- Geoffrey E Ciarlone
- Undersea Medicine Department, Naval Medical Research Center, 503 Robert Grant Ave., Silver Spring, MD, USA
| | - Christopher M Hinojo
- Department of Molecular Pharmacology and Physiology, Hyperbaric Biomedical Research Laboratory, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Nicole M Stavitzski
- Department of Molecular Pharmacology and Physiology, Hyperbaric Biomedical Research Laboratory, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Jay B Dean
- Department of Molecular Pharmacology and Physiology, Hyperbaric Biomedical Research Laboratory, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
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14
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Wilson DF, Matschinsky FM. Hyperbaric oxygen toxicity in brain: A case of hyperoxia induced hypoglycemic brain syndrome. Med Hypotheses 2019; 132:109375. [PMID: 31454640 DOI: 10.1016/j.mehy.2019.109375] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 08/09/2019] [Accepted: 08/18/2019] [Indexed: 12/25/2022]
Abstract
Hyperbaric oxygen exposure is a recent hazzard for higher animals that originated as humans began underwater construction, exploration, and sports. Exposure can lead to abnormal brain EEG, convulsions, and death, the time to onset of each stage of pathology decreasing with increase in oxygen pressure. We provide evidence that hyperoxia, through oxidative phosphorylation, increases the energy state ([ATP]/[ADP][Pi]) of cells critical to providing glucose to cells behind the blood brain barrier (BBB). Brain cells without an absolute dependence on glucose metabolism; i.e. those having sufficient ATP synthesis using lactate and glutamate as oxidizable substrates, are not themselves very adversely affected by hyperoxia. The increased energy state and decrease in free [AMP], however, suppress glucose transport through the blood brain barrier (BBB) and into cells behind the BBB. Glucose has to pass in sequence through three steps of transport by facilitated diffusion and transporter activity for each step is regulated in part by AMP dependent protein kinase. The physiological role of this regulation is to increase glucose transport in response to hypoxia and/or systemic hypoglycemia. Hyperoxia, however, through unphysiological decrease in free [AMP] suppresses 1) glucose transport through the BBB (endothelial GLUT1 transporters) into cerebrospinal fluid (CSF); 2) glucose transport from CSF into cells behind the BBB (GLUT3 transporters) and (GLUT4 transporters). Cumulative suppression of glucose transport results in local regions of hypoglycemia and induces hypoglycemic failure. It is suggested that failure is initiated at axons and synapses with insufficient mitochondria to meet their energy requirements.
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Affiliation(s)
- David F Wilson
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Franz M Matschinsky
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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15
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Choi J, Kwon HJ, Lee JE, Lee Y, Seoh JY, Han PL. Hyperoxygenation revitalizes Alzheimer's disease pathology through the upregulation of neurotrophic factors. Aging Cell 2019; 18:e12888. [PMID: 30746828 PMCID: PMC6413661 DOI: 10.1111/acel.12888] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 10/28/2018] [Accepted: 11/18/2018] [Indexed: 01/01/2023] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disease characterized by Aβ‐induced pathology and progressive cognitive decline. The incidence of AD is growing globally, yet a prompt and effective remedy is not available. Aging is the greatest risk factor for AD. Brain aging proceeds with reduced vascularization, which can cause low oxygen (O2) availability. Accordingly, the question may be raised whether O2 availability in the brain affects AD pathology. We found that Tg‐APP/PS1 mice treated with 100% O2 at increased atmospheric pressure in a chamber exhibited markedly reduced Aβ accumulation and hippocampal neuritic atrophy, increased hippocampal neurogenesis, and profoundly improved the cognitive deficits on the multiple behavioral test paradigms. Hyperoxygenation treatment increased the expression of BDNF, NT3, and NT4/5 through the upregulation of MeCP2/p‐CREB activity in HT22 cells in vitro and in the hippocampus of mice. In contrast, siRNA‐mediated inhibition of MeCP2 or TrkB neurotrophin receptors in the hippocampal subregion, which suppresses neurotrophin expression and neurotrophin action, respectively, blocked the therapeutic effects of hyperoxygenation on the cognitive impairments of Tg‐APP/PS1 mice. Our results highlight the importance of the O2‐related mechanisms in AD pathology, which can be revitalized by hyperoxygenation treatment, and the therapeutic potential of hyperoxygenation for AD.
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Affiliation(s)
- Juli Choi
- Department of Brain and Cognitive Sciences; Ewha Womans University; Seoul Korea
| | - Hye-Jin Kwon
- Department of Brain and Cognitive Sciences; Ewha Womans University; Seoul Korea
| | - Jung-Eun Lee
- Department of Brain and Cognitive Sciences; Ewha Womans University; Seoul Korea
| | - Yunjin Lee
- Department of Brain and Cognitive Sciences; Ewha Womans University; Seoul Korea
| | - Ju-Young Seoh
- Department of Microbiology, College of Medicine; Ewha Womans University; Seoul Korea
| | - Pyung-Lim Han
- Department of Brain and Cognitive Sciences; Ewha Womans University; Seoul Korea
- Department of Chemistry and Nano Science; Ewha Womans University; Seoul Korea
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16
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Immediate and delayed hyperbaric oxygen therapy as a neuroprotective treatment for traumatic brain injury in mice. Mol Cell Neurosci 2017; 83:74-82. [DOI: 10.1016/j.mcn.2017.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 06/19/2017] [Accepted: 06/19/2017] [Indexed: 01/29/2023] Open
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17
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Demchenko IT, Zhilyaev SY, Moskvin AN, Krivchenko AI, Piantadosi CA, Allen BW. Antiepileptic drugs prevent seizures in hyperbaric oxygen: A novel model of epileptiform activity. Brain Res 2017; 1657:347-354. [DOI: 10.1016/j.brainres.2016.12.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 12/29/2016] [Accepted: 12/31/2016] [Indexed: 11/25/2022]
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18
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Poff AM, Kernagis D, D'Agostino DP. Hyperbaric Environment: Oxygen and Cellular Damage versus Protection. Compr Physiol 2016; 7:213-234. [PMID: 28135004 DOI: 10.1002/cphy.c150032] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The elevation of tissue pO2 induced by hyperbaric oxygen (HBO) is a physiological stimulus that elicits a variety of cellular responses. These effects are largely mediated by, or in response to, an increase in the production of reactive oxygen and nitrogen species (RONS). The major consequences of elevated RONS include increased oxidative stress and enhanced antioxidant capacity, and modulation of redox-sensitive cell signaling pathways. Interestingly, these phenomena underlie both the therapeutic and potentially toxic effects of HBO. Emerging evidence indicates that supporting mitochondrial health is a potential method of enhancing the therapeutic efficacy of, and preventing oxygen toxicity during, HBO. This review will focus on the cellular consequences of HBO, and explore how these processes mediate a delicate balance of cellular protection versus damage. © 2017 American Physiological Society. Compr Physiol 7:213-234, 2017.
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Affiliation(s)
- Angela M Poff
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Dawn Kernagis
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Dominic P D'Agostino
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA.,Institute for Human and Machine Cognition, Pensacola, Florida, USA
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19
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Freiberger JJ, Derrick BJ, Natoli MJ, Akushevich I, Schinazi EA, Parker C, Stolp BW, Bennett PB, Vann RD, Dunworth SAS, Moon RE. Assessment of the interaction of hyperbaric N2, CO2, and O2 on psychomotor performance in divers. J Appl Physiol (1985) 2016; 121:953-964. [PMID: 27633739 DOI: 10.1152/japplphysiol.00534.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/02/2016] [Indexed: 11/22/2022] Open
Abstract
Diving narcosis results from the complex interaction of gases, activities, and environmental conditions. We hypothesized that these interactions could be separated into their component parts. Where previous studies have tested single cognitive tasks sequentially, we varied inspired partial pressures of CO2, N2, and O2 in immersed, exercising subjects while assessing multitasking performance with the Multi-Attribute Task Battery II (MATB-II) flight simulator. Cognitive performance was tested under 20 conditions of gas partial pressure and exercise in 42 male subjects meeting U.S. Navy age and fitness profiles. Inspired nitrogen (N2) and oxygen (O2) partial pressures were 0, 4.5, and 5.6 ATA and 0.21, 1.0, and 1.22 ATA, respectively, at rest and during 100-W immersed exercise with and without 0.075-ATA CO2 Linear regression modeled the association of gas partial pressure with task performance while controlling for exercise, hypercapnic ventilatory response, dive training, video game frequency, and age. Subjects served as their own controls. Impairment of memory, attention, and planning, but not motor tasks, was associated with N2 partial pressures >4.5 ATA. Sea level O2 at 0.925 ATA partially rescued motor and memory reaction time impaired by 0.075-ATA CO2; however, at hyperbaric pressures an unexpectedly strong interaction between CO2, N2, and exercise caused incapacitating narcosis with amnesia, which was augmented by O2 Perception of narcosis was not correlated with actual scores. The relative contributions of factors associated with diving narcosis will be useful to predict the effects of gas mixtures and exercise conditions on the cognitive performance of divers. The O2 effects are consistent with O2 narcosis or enhanced O2 toxicity.
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Affiliation(s)
- J J Freiberger
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - B J Derrick
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - M J Natoli
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - I Akushevich
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - E A Schinazi
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - C Parker
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - B W Stolp
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - P B Bennett
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - R D Vann
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - S A S Dunworth
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - R E Moon
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
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20
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Cardenas DP, Muir ER, Duong TQ. MRI of cerebral blood flow under hyperbaric conditions in rats. NMR IN BIOMEDICINE 2016; 29:961-968. [PMID: 27192391 PMCID: PMC4998963 DOI: 10.1002/nbm.3555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 03/03/2016] [Accepted: 04/11/2016] [Indexed: 06/05/2023]
Abstract
Hyperbaric oxygen (HBO) therapy has a number of clinical applications. However, the effects of acute HBO on basal cerebral blood flow (CBF) and neurovascular coupling are not well understood. This study explored the use of arterial spin labeling MRI to evaluate changes in baseline and forepaw stimulus-evoked CBF responses in rats (n = 8) during normobaric air (NB), normobaric oxygen (NBO) (100% O2 ), 3 atm absolute (ATA) hyperbaric air (HB) and 3 ATA HBO conditions. T1 was also measured, and the effects of changes in T1 caused by increasing oxygen on the CBF calculation were investigated. The major findings were as follows: (i) increased inhaled oxygen concentrations led to a reduced respiration rate; (ii) increased dissolved paramagnetic oxygen had significant effects on blood and tissue T1 , which affected the CBF calculation using the arterial spin labeling method; (iii) the differences in blood T1 had a larger effect than the differences in tissue T1 on CBF calculation; (iv) if oxygen-induced changes in blood and tissue T1 were not taken into account, CBF was underestimated by 33% at 3 ATA HBO, 10% at NBO and <5% at HB; (v) with correction, CBF values under HBO, HB and NBO were similar (p > 0.05) and all were higher than CBF under NB by ~40% (p < 0.05), indicating that hypercapnia from the reduced respiration rate masks oxygen-induced vasoconstriction, although blood gas was not measured; and (vi) substantial stimulus-evoked CBF increases were detected under HBO, similar to NB, supporting the notion that activation-induced CBF regulation in the brain does not operate through an oxygen-sensing mechanism. CBF MRI provides valuable insights into the effects of oxygen on basal CBF and neurovascular coupling under hyperbaric conditions. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Damon P. Cardenas
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
- Graduate School of Biomedical Science, University of Texas at San Antonio, San Antonio, TX, USA
| | - Eric R. Muir
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
- Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Timothy Q. Duong
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
- Department of Ophthalmology, University of Texas Health Science Center, San Antonio, TX, USA
- South Texas Veterans Health Care System, Department of Veterans Affairs, San Antonio, TX, USA
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21
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Eynan M, Mullokandov M, Krinsky N, Biram A, Arieli Y. Alteration of blood glucose levels in the rat following exposure to hyperbaric oxygen. J Appl Physiol (1985) 2015; 119:463-7. [PMID: 26183474 DOI: 10.1152/japplphysiol.00154.2015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 07/15/2015] [Indexed: 01/12/2023] Open
Abstract
Findings regarding blood glucose level (BGL) on exposure to hyperbaric oxygen (HBO) are contradictory. We investigated the influence of HBO on BGL, and of BGL on latency to central nervous system oxygen toxicity (CNS-OT). The study was conducted on five groups of rats: Group 1, exposure to oxygen at 2.5 atmospheres absolute (ATA), 90 min/day for 7 days; Group 2, exposure to oxygen once a week from 2 to 6 ATA in increments of 1 ATA/wk, for a period of time calculated as 60% of the latency to CNS-OT (no convulsions); Group 3, exposure to 6 ATA breathing a gas mixture with a pO2 of 0.21; Group 4, received 10 U/kg insulin to induce hypoglycemia before exposure to HBO; Group 5, received 33% glucose to induce hyperglycemia before exposure to HBO. Blood samples were drawn before and after exposures for measurement of BGL. No change was observed in BGL after exposure to oxygen at 2.5 ATA, 90 min/day for 7 days. BGL was significantly elevated after exposure to oxygen at 6 ATA until the appearance of convulsions, and following exposure to 4, 5, and 6 ATA without convulsions (P < 0.01). No change was observed in BGL after exposure to 6 ATA breathing a gas mixture with a pO2 of 0.21. Hypoglycemia shortened latency to CNS oxygen toxicity, whereas hyperglycemia had no effect. Our results demonstrate an influence of HBO exposure on elevation of BGL, starting at 4 ATA. This implies that BGL may serve as a marker for the generation of CNS-OT.
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Affiliation(s)
- Mirit Eynan
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Michael Mullokandov
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Nitzan Krinsky
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Adi Biram
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Yehuda Arieli
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
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22
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Kibel A, Novak S, Cosic A, Mihaljevic Z, Falck JR, Drenjancevic I. Hyperbaric oxygenation modulates vascular reactivity to angiotensin-(1-7) in diabetic rats: potential role of epoxyeicosatrienoic acids. Diab Vasc Dis Res 2015; 12:33-45. [PMID: 25326234 DOI: 10.1177/1479164114553424] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Previously, a facilitating effect of hyperbaric oxygenation (HBO₂) on aortic ring responses to angiotensin-(1-7) in healthy rats was reported, with epoxyeicosatrienoic acids (EETs) possibly playing an important role. The aim of this study was to assess whether HBO₂ exerts similar effects in diabetic rats and to further explore the role of specific cytochrome P450 (CYP) enzymes in changes induced by HBO₂. Aortic relaxation to angiotensin-(1-7) was significantly higher in HBO₂ diabetic rats compared to control diabetic rats, while HBO₂ had no effect on angiotensin II contraction. N-methylsulphonyl-6-(2-propargyloxyphenyl/hexanamide inhibited the facilitation of angiotensin-(1-7) responses in HBO₂ rats, suggesting an important role of EETs in this modulation. mRNA expression of CYP2J3 and protein expression of CYP2C11 were significantly upregulated in HBO₂ diabetic rats, whereas CYP4A1, CYP4A2 and CYP4A3 mRNA and CYP2J3 protein expression was similar between groups. Mean arterial pressure, ferric reducing ability of plasma and Thiobarbituric Acid Reactive Substances levels and serum angiotensin-(1-7) concentrations were not significantly changed.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/metabolism
- Amides/pharmacology
- Angiotensin I/blood
- Angiotensin I/pharmacology
- Angiotensin II/pharmacology
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Aorta, Thoracic/physiopathology
- Aryl Hydrocarbon Hydroxylases/antagonists & inhibitors
- Aryl Hydrocarbon Hydroxylases/genetics
- Aryl Hydrocarbon Hydroxylases/metabolism
- Cytochrome P-450 Enzyme System/chemistry
- Cytochrome P-450 Enzyme System/genetics
- Cytochrome P-450 Enzyme System/metabolism
- Cytochrome P450 Family 2
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/physiopathology
- Diabetes Mellitus, Type 1/therapy
- Diabetic Angiopathies/prevention & control
- Enzyme Induction
- Enzyme Inhibitors/pharmacology
- Hyperbaric Oxygenation/adverse effects
- Male
- Oxidative Stress
- Peptide Fragments/blood
- Peptide Fragments/pharmacology
- Rats, Sprague-Dawley
- Steroid 16-alpha-Hydroxylase/antagonists & inhibitors
- Steroid 16-alpha-Hydroxylase/genetics
- Steroid 16-alpha-Hydroxylase/metabolism
- Vascular Resistance/drug effects
- Vasoconstriction/drug effects
- Vasodilation/drug effects
- Vasodilator Agents/blood
- Vasodilator Agents/pharmacology
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Affiliation(s)
| | - Sanja Novak
- Faculty of Medicine, University of Osijek, Osijek, Croatia
| | - Anita Cosic
- Faculty of Medicine, University of Osijek, Osijek, Croatia
| | | | - John R Falck
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
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The oxygen paradox of neurovascular coupling. J Cereb Blood Flow Metab 2014; 34:19-29. [PMID: 24149931 PMCID: PMC3887356 DOI: 10.1038/jcbfm.2013.181] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 09/12/2013] [Accepted: 09/22/2013] [Indexed: 01/09/2023]
Abstract
The coupling of cerebral blood flow (CBF) to neuronal activity is well preserved during evolution. Upon changes in the neuronal activity, an incompletely understood coupling mechanism regulates diameter changes of supplying blood vessels, which adjust CBF within seconds. The physiologic brain tissue oxygen content would sustain unimpeded brain function for only 1 second if continuous oxygen supply would suddenly stop. This suggests that the CBF response has evolved to balance oxygen supply and demand. Surprisingly, CBF increases surpass the accompanying increases of cerebral metabolic rate of oxygen (CMRO2). However, a disproportionate CBF increase may be required to increase the concentration gradient from capillary to tissue that drives oxygen delivery. However, the brain tissue oxygen content is not zero, and tissue pO2 decreases could serve to increase oxygen delivery without a CBF increase. Experimental evidence suggests that CMRO2 can increase with constant CBF within limits and decreases of baseline CBF were observed with constant CMRO2. This conflicting evidence may be viewed as an oxygen paradox of neurovascular coupling. As a possible solution for this paradox, we hypothesize that the CBF response has evolved to safeguard brain function in situations of moderate pathophysiological interference with oxygen supply.
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Drenjancevic I, Kibel A. Restoring Vascular Function with Hyperbaric Oxygen Treatment: Recovery Mechanisms. J Vasc Res 2013; 51:1-13. [DOI: 10.1159/000355925] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 09/05/2013] [Indexed: 11/19/2022] Open
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Moskvin AN, Luchakov YI. Oxygen tension in rat brain during hyperoxia [corrected]. Bull Exp Biol Med 2013; 154:435-7. [PMID: 23486574 DOI: 10.1007/s10517-013-1970-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Critical value of oxygen tension (Po2) and cerebral blood flow in the striatum for seizure appearance during hyperbaric oxygenation (5 ATA) were determined in awake Wistar rats. Seizure activity was observed at Po2=1030±102 mm Hg. A relationship between brain Po2 and blood flow was revealed at different regimens of hyperbaric oxygenation using a mathematical model. Comparison of experimental data and mathematical model showed that seizure-inducing levels of Po2during hyperbaric oxygenation at 4, 5, and 6 ATA can be achieved after increasing blood flow by 1.5-3.0, 1.2-2.0, and 0.8-1.1, respectively.
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Affiliation(s)
- A N Moskvin
- Laboratory for Hyperbaric Physiology, I. M. Sechenov Institute of Evolutional Physiology and Biochemistry, Russian Academy of Sciences, Sankt-Petersburg, Russia.
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Pilla R, Held HE, Landon CS, Dean JB. High doses of pseudoephedrine hydrochloride accelerate onset of CNS oxygen toxicity seizures in unanesthetized rats. Neuroscience 2013; 246:391-6. [PMID: 23624060 DOI: 10.1016/j.neuroscience.2013.04.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 04/15/2013] [Accepted: 04/16/2013] [Indexed: 11/16/2022]
Abstract
Pseudoephedrine (PSE) salts (hydrochloride and sulfate) are commonly used as nasal and paranasal decongestants by scuba divers. Anecdotal reports from the Divers Alert Network suggest that taking PSE prior to diving while breathing pure O₂ increases the risk for CNS oxygen toxicity (CNS-OT), which manifests as seizures. We hypothesized that high doses of PSE reduce the latency time to seizure (LS) in unanesthetized rats breathing 5 atmospheres absolute (ATA) of hyperbaric oxygen. Sixty-three male rats were implanted with radio-transmitters that recorded electroencephalogram activity and body temperature. After ≥7-day recovery, and 2 h before "diving", each rat was administered either saline solution (control) or PSE hydrochloride intragastrically at the following doses (mg PSE/kg): 0, 40, 80, 100, 120, 160, and 320. Rats breathed pure O₂ and were dived to 5ATA until the onset of behavioral seizures coincident with neurological seizures. LS was the time elapsed between reaching 5ATA and exhibiting seizures. We observed a significant dose-dependent decrease in the LS at doses of 100-320 mg/kg, whereas no significant differences in LS from control value were observed at doses ≤80 mg/kg. Our findings showed that high doses of PSE accelerate the onset of CNS-OT seizures in unanesthetized rats breathing 5ATA of poikilocapnic hyperoxia. Extrapolating our findings to humans, we conclude that the recommended daily dose of PSE should not be abused prior to diving with oxygen-enriched gas mixes or pure O₂.
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Affiliation(s)
- R Pilla
- Department of Molecular Pharmacology & Physiology, Hyperbaric Biomedical Research Laboratory, 12901 Bruce B. Downs Boulevard, University of South Florida, Morsani College of Medicine, MDC 8, Tampa, FL 33612, United States
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Pilla R, Landon CS, Dean JB. A potential early physiological marker for CNS oxygen toxicity: hyperoxic hyperpnea precedes seizure in unanesthetized rats breathing hyperbaric oxygen. J Appl Physiol (1985) 2013; 114:1009-20. [PMID: 23429869 DOI: 10.1152/japplphysiol.01326.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Hyperbaric oxygen (HBO(2)) stimulates presumptive central CO2-chemoreceptor neurons, increases minute ventilation (V(min)), decreases heart rate (HR) and, if breathed sufficiently long, produces central nervous system oxygen toxicity (CNS-OT; i.e., seizures). The risk of seizures when breathing HBO(2) is variable between individuals and its onset is difficult to predict. We have tested the hypothesis that a predictable pattern of cardiorespiration precedes an impending seizure when breathing HBO2. To test this hypothesis, 27 adult male Sprague-Dawley rats were implanted with radiotelemetry transmitters to assess diaphragmatic/abdominal electromyogram, electrocardiogram, and electroencephalogram. Seven days after surgery, each rat was placed in a sealed, continuously ventilated animal chamber inside a hyperbaric chamber. Both chambers were pressurized in parallel using poikilocapnic 100% O(2) (animal chamber) and air (hyperbaric chamber) to 4, 5, or 6 atmospheres absolute (ATA). Breathing 1 ATA O(2) initially decreased V(min) and HR (Phase 1 of the compound hyperoxic ventilatory response). With continued exposure to normobaric hyperoxia, however, V(min) began increasing toward the end of exposure in one-third of the animals tested. Breathing HBO2 induced an early transient increase in V(min) (Phase 2) and HR during the chamber pressurization, followed by a second significant increase of V(min) ≤8 min prior to seizure (Phase 3). HR, which subsequently decreased during sustained hyperoxia, showed no additional changes prior to seizure. We conclude that hyperoxic hyperpnea (Phase 3 of the compound hyperoxic ventilatory response) is a predictor of an impending seizure while breathing poikilocapnic HBO(2) at rest in unanesthetized rats.
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Affiliation(s)
- Raffaele Pilla
- Department of Molecular Pharmacology & Physiology, Hyperbaric Biomedical Research Laboratory, University of South Florida, Morsani College of Medicine, Tampa, FL 33612, USA
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Malek M, Duszczyk M, Zyszkowski M, Ziembowicz A, Salinska E. Hyperbaric oxygen and hyperbaric air treatment result in comparable neuronal death reduction and improved behavioral outcome after transient forebrain ischemia in the gerbil. Exp Brain Res 2012; 224:1-14. [PMID: 23283415 PMCID: PMC3535395 DOI: 10.1007/s00221-012-3283-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 09/19/2012] [Indexed: 12/20/2022]
Abstract
Anoxic brain injury resulting from cardiac arrest is responsible for approximately two-thirds of deaths. Recent evidence suggests that increased oxygen delivered to the brain after cardiac arrest may be an important factor in preventing neuronal damage, resulting in an interest in hyperbaric oxygen (HBO) therapy. Interestingly, increased oxygen supply may be also reached by application of normobaric oxygen (NBO) or hyperbaric air (HBA). However, previous research also showed that the beneficial effect of hyperbaric treatment may not directly result from increased oxygen supply, leading to the conclusion that the mechanism of hyperbaric prevention of brain damage is not well understood. The aim of our study was to compare the effects of HBO, HBA and NBO treatment on gerbil brain condition after transient forebrain ischemia, serving as a model of cardiac arrest. Thereby, we investigated the effects of repetitive HBO, HBA and NBO treatment on hippocampal CA1 neuronal survival, brain temperature and gerbils behavior (the nest building), depending on the time of initiation of the therapy (1, 3 and 6 h after ischemia). HBO and HBA applied 1, 3 and 6 h after ischemia significantly increased neuronal survival and behavioral performance and abolished the ischemia-evoked brain temperature increase. NBO treatment was most effective when applied 1 h after ischemia; later application had a weak or no protective effect. The results show that HBO and HBA applied between 1 and 6 h after ischemia prevent ischemia-evoked neuronal damage, which may be due to the inhibition of brain temperature increase, as a result of the applied rise in ambient pressure, and just not due to the oxygen per se. This perspective is supported by the finding that NBO treatment was less effective than HBO or HBA therapy. The results presented in this paper may pave the way for future experimental studies dealing with pressure and temperature regulation.
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Affiliation(s)
- Michal Malek
- Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Str., 02-106 Warsaw, Poland
| | - Malgorzata Duszczyk
- Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Str., 02-106 Warsaw, Poland
| | - Marcin Zyszkowski
- Department of Anesthesiology and Intensive Care, Military Institute of Medicine, Warsaw, Poland
| | - Apolonia Ziembowicz
- Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Str., 02-106 Warsaw, Poland
| | - Elzbieta Salinska
- Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Str., 02-106 Warsaw, Poland
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29
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Atochin DN, Huang PL. Role of endothelial nitric oxide in cerebrovascular regulation. Curr Pharm Biotechnol 2012; 12:1334-42. [PMID: 21235451 DOI: 10.2174/138920111798280974] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2010] [Revised: 07/01/2010] [Accepted: 08/08/2010] [Indexed: 11/22/2022]
Abstract
Endothelial nitric oxide (NO) plays important roles in the vascular system. Animal models that show vascular dysfunction demonstrate the protective role of endothelial NO dependent pathways. This review focuses on the role of endothelial NO in the regulation of cerebral blood flow and vascular tone. We will discuss the importance of NO in cerebrovascular function using animal models with altered endothelial NO production under normal, ischemic and reperfusion conditions, as well as in hyperoxia. Pharmacological and genetic manipulations of the endothelial NO system demonstrate the essential roles of endothelial NO synthase in maintenance of vascular tone and cerebral perfusion under normal and pathological conditions.
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Affiliation(s)
- Dmitriy N Atochin
- Cardiovascular Research Center and Cardiology Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129, USA.
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Demchenko IT, Mahon RT, Allen BW, Piantadosi CA. Brain oxygenation and CNS oxygen toxicity after infusion of perfluorocarbon emulsion. J Appl Physiol (1985) 2012; 113:224-31. [PMID: 22556400 DOI: 10.1152/japplphysiol.00308.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intravenous perfluorocarbon (PFC) emulsions, administered with supplemental inspired O(2), are being evaluated for their ability to eliminate N(2) from blood and tissue prior to submarine escape, but these agents can increase the incidence of central nervous system (CNS) O(2) toxicity, perhaps by enhancing O(2) delivery to the brain. To assess this, we infused a PFC emulsion (Oxycyte, 6 ml/kg iv) into anesthetized rats and measured cerebral Po(2) and regional cerebral blood flow (rCBF) in cortex, hippocampus, hypothalamus, and striatum with 100% O(2) at 1, 3, or 5 atmospheres absolute (ATA). At 1 ATA, brain Po(2) stabilized at >20 mmHg higher in animals infused with PFC emulsion than in control animals infused with saline, and rCBF fell by ~10%. At 3 ATA, PFC emulsion raised brain Po(2) >70 mmHg above control levels, and rCBF decreased by as much as 25%. At 5 ATA, brain Po(2) was ≥159 mmHg above levels in control animals for the first 40 min but then rose sharply; rCBF showed a similar profile, reflecting vasoconstriction followed by hyperemia. Conscious rats were also pretreated with PFC emulsion at 3 or 6 ml/kg iv and exposed to 100% O(2) at 5 ATA. At the lower dose, 80% of the animals experienced seizures by 33 min compared with 50% of the control animals. At the higher dose, seizures occurred in all rats within 25 min. At these doses, administration of PFC emulsion poses a clear risk of CNS O(2) toxicity in conscious rats exposed to hyperbaric O(2) at 5 ATA.
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Affiliation(s)
- Ivan T Demchenko
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC 27710, USA
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Ivanov A, Zilberter Y. Critical state of energy metabolism in brain slices: the principal role of oxygen delivery and energy substrates in shaping neuronal activity. FRONTIERS IN NEUROENERGETICS 2011; 3:9. [PMID: 22232599 PMCID: PMC3247678 DOI: 10.3389/fnene.2011.00009] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 12/10/2011] [Indexed: 12/22/2022]
Abstract
The interactive vasculo-neuro-glial system controlling energy supply in the brain is absent in vitro where energy provision is determined by experimental conditions. Despite the fact that neuronal activity is extremely energy demanding, little has been reported on the state of energy metabolism in submerged brain slices. Without this information, the arbitrarily chosen oxygenation and metabolic provisions make questionable the efficient oxidative metabolism in slices. We show that in mouse hippocampal slices (postnatal day 19–44), evoked neuronal discharges, spontaneous network activity (initiated by 4-aminopyridine), and synaptic stimulation-induced NAD(P)H autofluorescence depend strongly on the oxygen availability. Only the rate of perfusion as high as ~15 ml/min (95% O2) provided appropriate oxygenation of a slice. Lower oxygenation resulted in the decrease of both local field potentials and spontaneous network activity as well as in significant modulation of short-term synaptic plasticity. The reduced oxygen supply considerably inhibited the oxidation phase of NAD(P)H signaling indicating that the changes in neuronal activity were paralleled by the decrease in aerobic energy metabolism. Interestingly, the dependence of neuronal activity on oxygen tension was clearly shifted toward considerably larger pO2 values in slices when compared to in vivo conditions. With sufficient pO2 provided by a high perfusion rate, partial substitution of glucose in ACSF for β-hydroxybutyrate, pyruvate, or lactate enhanced both oxidative metabolism and synaptic function. This suggests that the high pO2 in brain slices is compulsory for maintaining oxidative metabolism, and glucose alone is not sufficient in fulfilling energy requirements during neuronal activity. Altogether, our results demonstrate that energy metabolism determines the functional state of neuronal network, highlighting the need for the adequate metabolic support to be insured in the in vitro experiments.
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Affiliation(s)
- Anton Ivanov
- INSERM UMR751, Université de la Méditerranée Marseille, France
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Eynan M, Tsitlovsky D, Batit L, Hochman A, Krinsky N, Abramovich A. Is glucose-6-phosphate dehydrogenase deficiency a risk factor for hyperbaric oxygen exposure? Eur J Appl Physiol 2011; 112:2549-56. [DOI: 10.1007/s00421-011-2229-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 10/27/2011] [Indexed: 10/15/2022]
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Srinivasan VJ, Atochin DN, Radhakrishnan H, Jiang JY, Ruvinskaya S, Wu W, Barry S, Cable AE, Ayata C, Huang PL, Boas DA. Optical coherence tomography for the quantitative study of cerebrovascular physiology. J Cereb Blood Flow Metab 2011; 31:1339-45. [PMID: 21364599 PMCID: PMC3130321 DOI: 10.1038/jcbfm.2011.19] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Doppler optical coherence tomography (DOCT) and OCT angiography are novel methods to investigate cerebrovascular physiology. In the rodent cortex, DOCT flow displays features characteristic of cerebral blood flow, including conservation along nonbranching vascular segments and at branch points. Moreover, DOCT flow values correlate with hydrogen clearance flow values when both are measured simultaneously. These data validate DOCT as a noninvasive quantitative method to measure tissue perfusion over a physiologic range.
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Affiliation(s)
- Vivek J Srinivasan
- Department of Radiology, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA.
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Abstract
Acute ischemic stroke (AIS) results in focal deprivation of blood-borne factors, one of them being oxygen. The purpose of this study was two-fold: (1) to identify therapeutic conditions for supplemental oxygen in AIS and (2) to use transcriptome-wide screening toward uncovering oxygen-sensitive mechanisms. Transient MCAO in rodents was used to delineate the therapeutic potential of normobaric (NBO, 100% O(2), 1ATA) and hyperbaric oxygen (HBO, 100% O(2), 2ATA) during ischemia (iNBO, iHBO) and after reperfusion (rNBO, rHBO). Stroke lesion was quantified using 4.7 T MRI at 48 h. Supplemental oxygen during AIS significantly attenuated percent stroke hemisphere lesion volume as compared with that in room air (RA) controls, whereas identical treatment immediately after reperfusion exacerbated lesion volume (RA=22.4+/-1.8, iNBO=9.9+/-3.6, iHBO=6.6+/-4.8, rNBO=29.8+/-3.6, rHBO=35.4+/-7.6). iNBO and iHBO corrected penumbra tissue pO(2) during AIS as measured by EPR oxymetry. Unbiased query of oxygen-sensitive transcriptome in stroke-affected tissue identified 5,769 differentially expressed genes. Candidate genes were verified by real-time PCR using neurons laser-captured from the stroke-affected somatosensory cortex. Directed microarray analysis showed that supplemental oxygen limited leukocyte accumulation to the infarct site by attenuation of stroke-inducible proinflammatory chemokine response. The findings provide key information relevant to understanding oxygen-dependent molecular mechanisms in the AIS-affected brain.
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Abstract
Recently, a universal, simple, and fail-safe mechanism has been proposed by which cerebral blood flow (CBF) might be coupled to oxygen metabolism during neuronal activation without the need for any tissue-based mechanism. According to this concept, vasodilation occurs by local erythrocytic release of nitric oxide or ATP wherever and whenever hemoglobin is deoxygenated, directly matching oxygen demand and supply in every tissue. For neurovascular coupling in the brain, we present experimental evidence challenging this view by applying an experimental regime operating without deoxy-hemoglobin. Hyperbaric hyperoxygenation (HBO) allowed us to prevent hemoglobin deoxygenation, as the oxygen that was physically dissolved in the tissue was sufficient to support oxidative metabolism. Regional CBF and regional cerebral blood oxygenation were measured using a cranial window preparation in anesthetized rats. Hemodynamic and neuronal responses to electrical forepaw stimulation or cortical spreading depression (CSD) were analyzed under normobaric normoxia and during HBO up to 4 ATA (standard atmospheres absolute). Inconsistent with the proposed mechanism, during HBO, CBF responses to functional activation or CSD were unchanged. Our results show that activation-induced CBF regulation in the brain does not operate through the release of vasoactive mediators on hemoglobin deoxygenation or through a tissue-based oxygen-sensing mechanism.
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Rioja E, Kerr CL, McDonell WN, Dobson H, Konyer NB, Poma R, Noseworthy MD. Effects of hypercapnia, hypocapnia, and hyperoxemia on blood oxygenation level-dependent signal intensity determined by use of susceptibility-weighted magnetic resonance imaging in isoflurane-anesthetized dogs. Am J Vet Res 2010; 71:24-32. [PMID: 20043777 DOI: 10.2460/ajvr.71.1.24] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To assess the effects of alterations in PaCO(2) and PaO(2) on blood oxygenation level-dependent (BOLD) signal intensity determined by use of susceptibility-weighted magnetic resonance imaging in brains of isoflurane-anesthetized dogs. ANIMALS 6 healthy dogs. PROCEDURES In each dog, anesthesia was induced with propofol (6 to 8 mg/kg, IV) and maintained with isoflurane (1.7%) and atracurium (0.2 mg/kg, IV, q 30 min). During 1 magnetic resonance imaging session in each dog, targeted values of PaCO(2) (20, 40, or 80 mm Hg) and PaO(2) (100 or 500 mm Hg) were combined to establish 6 experimental conditions, including a control condition (PaCO(2), 40 mm Hg; PaO(2), 100 mm Hg). Dogs were randomly assigned to different sequences of conditions. Each condition was established for a period of >or= 5 minutes before susceptibility-weighted imaging was performed. Signal intensity was measured in 6 regions of interest in the brain, and data were analyzed by use of an ANCOVA and post hoc Tukey-Kramer adjustments. RESULTS Compared with control condition findings, BOLD signal intensity did not differ significantly in any region of interest. However, signal intensities in the thalamus and diencephalic gray matter decreased significantly during both hypocapnic conditions, compared with all other conditions except for the control condition. CONCLUSIONS AND CLINICAL RELEVANCE In isoflurane-anesthetized dogs, certain regions of gray matter appeared to have greater cerebrovascular responses to changes in PaCO(2) and PaO(2) than did others. Both PaO(2) and PaCO(2) should be controlled during magnetic resonance imaging procedures that involve BOLD signaling and taken into account when interpreting findings.
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Affiliation(s)
- Eva Rioja
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
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Involvement of Extracellular Superoxide Dismutase in Regulating Brain Blood Flow. ACTA ACUST UNITED AC 2009; 40:173-8. [DOI: 10.1007/s11055-009-9240-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2008] [Revised: 10/07/2008] [Indexed: 10/20/2022]
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Demchenko IT, Ruehle A, Allen BW, Vann RD, Piantadosi CA. Phosphodiesterase-5 inhibitors oppose hyperoxic vasoconstriction and accelerate seizure development in rats exposed to hyperbaric oxygen. J Appl Physiol (1985) 2009; 106:1234-42. [PMID: 19179645 DOI: 10.1152/japplphysiol.91407.2008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Oxygen is a potent cerebral vasoconstrictor, but excessive exposure to hyperbaric oxygen (HBO(2)) can reverse this vasoconstriction by stimulating brain nitric oxide (NO) production, which increases cerebral blood flow (CBF)-a predictor of O(2) convulsions. We tested the hypothesis that phosphodiesterase (PDE)-5 blockers, specifically sildenafil and tadalafil, increase CBF in HBO(2) and accelerate seizure development. To estimate changes in cerebrovascular responses to hyperoxia, CBF was measured by hydrogen clearance in anesthetized rats, either control animals or those pretreated with one of these blockers, with the NO inhibitor N(omega)-nitro-l-arginine methyl ester (l-NAME), with the NO donor S-nitroso-N-acetylpenicillamine (SNAP), or with a blocker combined with l-NAME. Animals were exposed to 30% O(2) at 1 atm absolute (ATA) ("air") or to 100% O(2) at 4 or 6 ATA. EEG spikes indicated central nervous system CNS O(2) toxicity. The effects of PDE-5 blockade varied as a positive function of ambient Po(2). In air, CBF did not increase significantly, except after pretreatment with SNAP. However, at 6 ATA O(2), mean values for CBF increased and values for seizure latency decreased, both significantly; pretreatment with l-NAME abolished these effects. Conscious rats treated with sildenafil before HBO(2) were also more susceptible to CNS O(2) toxicity, as demonstrated by significantly shortened convulsive latency. Decreases in regional CBF reflect net vasoconstriction in the brain regions studied, since mean arterial pressures remained constant or increased throughout. Thus PDE-5 blockers oppose the protective vasoconstriction that is the initial response to hyperbaric hyperoxia, decreasing the safety of HBO(2) by hastening onset of CNS O(2) toxicity.
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Affiliation(s)
- Ivan T Demchenko
- Center for Hyperbaric Medicine and Environmental Physiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
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Transient hypoxia stimulates mitochondrial biogenesis in brain subcortex by a neuronal nitric oxide synthase-dependent mechanism. J Neurosci 2008; 28:2015-24. [PMID: 18305236 DOI: 10.1523/jneurosci.5654-07.2008] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The adaptive mechanisms that protect brain metabolism during and after hypoxia, for instance, during hypoxic preconditioning, are coordinated in part by nitric oxide (NO). We tested the hypothesis that acute transient hypoxia stimulates NO synthase (NOS)-activated mechanisms of mitochondrial biogenesis in the hypoxia-sensitive subcortex of wild-type (Wt) and neuronal NOS (nNOS) and endothelial NOS (eNOS)-deficient mice. Mice were exposed to hypobaric hypoxia for 6 h, and changes in immediate hypoxic transcriptional regulation of mitochondrial biogenesis was assessed in relation to mitochondrial DNA (mtDNA) content and mitochondrial density. There were no differences in cerebral blood flow or hippocampal PO2 responses to acute hypoxia among these strains of mice. In Wt mice, hypoxia increased mRNA levels for peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1 alpha), nuclear respiratory factor-1, and mitochondrial transcription factor A. After 24 h, new mitochondria, localized in reporter mice expressing mitochondrial green fluorescence protein, were seen primarily in hippocampal neurons. eNOS-/- mice displayed lower basal levels but maintained hypoxic induction of these transcripts. In contrast, nuclear transcriptional regulation of mitochondrial biogenesis in nNOS-/- mice was normal at baseline but did not respond to hypoxia. After hypoxia, subcortical mtDNA content increased in Wt and eNOS-/- mice but not in nNOS-/- mice. Hypoxia stimulated PGC-1alpha protein expression and phosphorylation of protein kinase A and cAMP response element binding (CREB) protein in Wt mice, but CREB only was activated in eNOS-/- mice and not in nNOS-/- mice. These findings demonstrate that hypoxic preconditioning elicits subcortical mitochondrial biogenesis by a novel mechanism that requires nNOS regulation of PGC-1alpha and CREB.
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Sun L, Marti HH, Veltkamp R. Hyperbaric oxygen reduces tissue hypoxia and hypoxia-inducible factor-1 alpha expression in focal cerebral ischemia. Stroke 2008; 39:1000-6. [PMID: 18239183 DOI: 10.1161/strokeaha.107.490599] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND AND PURPOSE The usefulness of hyperbaric oxygen (HBO) and normobaric hyperoxia in acute ischemic stroke is being reexplored because both improve outcome in experimental cerebral ischemia. However, even the basic mechanisms underlying oxygen therapy are poorly understood. We investigated the effect of both oxygen therapies on tissue hypoxia and on the transcription factor hypoxia-inducible factor-1 alpha. METHODS Mice were subjected to filament-induced middle cerebral artery occlusion for 2 hours. Twenty-five minutes after filament introduction, mice breathed normobaric air, normobaric 100% O(2) (normobaric hyperoxia), or 100% O(2) at 3 ata (HBO) for 95 minutes. Hypoxic regions were mapped on tissue sections after preischemic infusion of the in vivo hypoxia marker EF-5. Hypoxia-inducible factor-1 alpha protein was measured after 2-hour middle cerebral artery occlusion using immunofluorescence and immunoblotting. Vascular endothelial growth factor expression was analyzed using in situ mRNA hybridization. RESULTS Severity of ischemia did not differ among groups. HBO (35.2+/-10.4 mm(2)) significantly reduced the area of EF-5-stained hypoxic regions in focal cerebral ischemia compared with normobaric hyperoxia (46.4+/-11.2 mm(2)) and air (49.1+/-8 mm(2), P<0.05, analysis of variance). Topographically, EF-5 fluorescence was decreased in medial striatum and in cortical ischemic border areas. Immunohistochemistry and immunoblotting revealed lower hypoxia-inducible factor-1 alpha protein in the ischemic hemisphere of HBO-treated mice. Moreover, mRNA in situ hybridization showed lower expression of vascular endothelial growth factor in HBO and normobaric hyperoxia groups. CONCLUSIONS Measurement of extrinsic and intrinsic markers of hypoxia revealed that HBO improves penumbral oxygenation in focal ischemia. Modification of the transcription factor hypoxia-inducible factor-1 alpha and its downstream targets may be involved in effects of HBO.
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Affiliation(s)
- Li Sun
- Department of Neurology, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany
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Ohgami Y, Chung E, Shirachi DY, Quock RM. The effect of hyperbaric oxygen on regional brain and spinal cord levels of nitric oxide metabolites in rat. Brain Res Bull 2007; 75:668-73. [PMID: 18355644 DOI: 10.1016/j.brainresbull.2007.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 11/05/2007] [Accepted: 11/06/2007] [Indexed: 11/28/2022]
Abstract
Hyperbaric oxygen (HBO(2)) therapy is reported to be beneficial in transient brain ischemia. The present study was conducted to determine the influence of HBO(2) on metabolites of nitric oxide (NO) in brain and spinal cord of rats. Rats were exposed to room air (RA), normobaric air (NBA), normobaric oxygen (NBO(2)), hyperbaric air (HBA) or HBO(2), the last two conditions at 2.5ATA (atmosphere absolute) for 60 min. The results demonstrate that, compared to the NBA control, oxygen alone generally reduced tissue levels of NO(x)(-) (nitrite plus nitrate). On the other hand, 2.5ATA alone tended to have a slight, if any, effect on tissue levels of NO(x)(-). The combination of oxygen and pressure (i.e., HBO(2)) generally led to an increase in tissue levels of NO(x)(-). Based on these findings, it is concluded that HBO(2) appears to markedly increase NO function most notably in the corpus striatum, brainstem, cerebellum and spinal cord.
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Affiliation(s)
- Yusuke Ohgami
- Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, Pullman, WA 99164-6534, USA
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Hou H, Grinberg O, Williams B, Grinberg S, Yu H, Alvarenga DL, Wallach H, Buckey J, Swartz HM. The effect of oxygen therapy on brain damage and cerebral pO(2) in transient focal cerebral ischemia in the rat. Physiol Meas 2007; 28:963-76. [PMID: 17664686 DOI: 10.1088/0967-3334/28/8/017] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We examined the effect of hyperbaric oxygen (HBO) and normobaric oxygen (NBO) on neurologic damage and brain oxygenation before and after focal cerebral ischemia in rats. A middle cerebral artery occlusion (MCAO)/reperfusion rat model was used. The rats were sacrificed 22 h after reperfusion, and the infarct volume was evaluated. In study A, HBO (2.0 ATA), NBO (100% oxygen) and normobaric air (NBA) were each administered for 60 min in five different rat groups. The sizes of the infarcts after HBO and NBO applied during ischemia were 8.8 +/- 2.8% and 22.8 +/- 3.7% respectively of the ipsilateral non-occluded hemisphere. The infarct size after HBO applied during ischemia was statistically smaller than for NBO and NBA exposure (p < 0.01). In study B, cerebral pO(2) was measured before and after MCAO and HBO exposure (2.0 ATA for 60 min) in six rats using electron paramagnetic resonance (EPR) oximetry. The pO(2) in the ischemic hemisphere fell markedly following ischemia, while the pO(2) in the contralateral hemisphere remained within the normal range. Measurements of the pO(2) performed minutes after HBO exposure did not show an increase in the ischemic or normal hemispheres. The mean relative infarct size was consistent with the changes observed in study A. These data confirm the neuroprotective effects of HBO in cerebral ischemia and indicate that in vivo EPR oximetry can be an effective method to monitor the cerebral oxygenation after oxygen therapy for ischemic stroke. The ability to measure the pO(2) in several sites provides important information that should help to optimize the design of hyperoxic therapies for stroke.
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Affiliation(s)
- Huagang Hou
- Department of Radiology, Dartmouth Medical School, Hanover, NH, USA
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Abstract
Hyperbaric oxygen (HBO) therapy is defined by the Undersea and Hyperbaric Medical Society (UHMS) as a treatment in which a patient intermittingly breathes 100% oxygen under a pressure that is greater than the pressure at sea level [a pressure greater than 1 atmosphere absolute (ATA)]. HBO has been shown to be a potent means to increase the oxygen content of blood and has been advocated for the treatment of various ailments, including air embolism, carbon monoxide poisoning, wound healing and ischemic stroke. However, definitive established mechanisms of action are still lacking. This has led to uncertainty among clinicians, who have understandingly become hesitant in regard to using HBO therapy, even in situations where it could prove beneficial. Therefore, this review will summarize the literature regarding the effects of HBO on brain oxygenation, cerebral blood flow and intracranial pressure in both the healthy and injured brains, as well as discuss how changes in these three factors can impart protection.
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Affiliation(s)
- John W Calvert
- Department of Physiology, Division of Neurosurgery, Loma Linda University Medical Center, Loma Linda, CA, USA.
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Meirovithz E, Sonn J, Mayevsky A. Effect of hyperbaric oxygenation on brain hemodynamics, hemoglobin oxygenation and mitochondrial NADH. ACTA ACUST UNITED AC 2007; 54:294-304. [PMID: 17570266 DOI: 10.1016/j.brainresrev.2007.04.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 04/22/2007] [Accepted: 04/23/2007] [Indexed: 11/19/2022]
Abstract
To determine the HbO(2) oxygenation level at the microcirculation, we used the hyperbaric chamber. The effects of hyperbaric oxygenation (HBO) were tested on vitality parameters in the brain at various pressures. Microcirculatory hemoglobin oxygen saturation (HbO(2)), cerebral blood flow (CBF) and mitochondrial NADH redox state were assessed in the brain of awake restrained rats using a fiber optic probe. The hypothesis was that HBO may lead to maximal level in microcirculatory HbO(2) due to the amount of the dissolved O(2) to provide the O(2) consumed by the brain, and therefore no O(2) will be dissociated from the HbO(2). Awake rats were exposed progressively to 15 min normobaric hyperoxia, 100% O(2) (NH) and to 90 min hyperbaric hyperoxia (HH) from 1.75 to 6.0 absolute atmospheres (ATA). NH and HH gradually decreased the blood volume measured by tissue reflectance and NADH but increased HbO(2) in relation to pO(2) in the chamber up to a nearly maximum effect at 2.5 ATA. Two possible approximations were found to describe the relationship between NADH and HbO(2): linear or logarithmic. These findings show that the increase in brain microcirculatory HbO(2) is due to an increase in O(2) supply by dissolved O(2), reaching a maximum at 2.5 ATA. NADH is oxidized (decreased signal) in parallel to the HbO(2) increase, showing maximal tissue oxygenation and cellular mitochondrial NADH oxidation at 2.5 ATA. In conclusion, in the normoxic brain, the level of microcirculatory HbO(2) is about 50% as compared to the maximal level recorded at 2.5 ATA and the minimal level measured during anoxia.
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Affiliation(s)
- Elhanan Meirovithz
- The Mina & Everard Goodman Faculty of Life Sciences and the Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 52900, Israel
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Time-dependent effects of hyperoxia on the BOLD fMRI signal in primate visual cortex and LGN. Neuroimage 2007; 35:1044-63. [PMID: 17321759 DOI: 10.1016/j.neuroimage.2006.12.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Revised: 08/24/2006] [Accepted: 12/12/2006] [Indexed: 11/28/2022] Open
Abstract
Hyperoxia is present in many anaesthesia protocols used in animal blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) studies. However, little data exist on the influence of hyperoxia on the magnitude of stimulus-induced relative changes in BOLD fMRI signal (DeltaBOLD%). No study to date has investigated these effects in a time-resolved manner, although cerebral vasoregulation offers sites for a time-dependent interaction of hyperoxia and DeltaBOLD%. Here we investigated time-dependent effects of an inspiratory oxygen fraction of 90%. We tightly clamped end tidal CO(2) and body temperature and recorded physiological parameters relevant to rCBF in (fentanyl/isoflurane) anaesthetized monkeys while using visual stimulation to elicit DeltaBOLD%. To clarify whether changes in DeltaBOLD% arose from changes in baseline blood oxygenation or rather altered neuronal or vascular reactivity, we directly measured changes in rCBV using monocrystalline ion oxide nanoparticles (MION) as contrast agent. In visual cortex we found a biphasic modulation of stimulus-induced DeltaBOLD% under hyperoxia: We observed first a significant decrease in DeltaBOLD% by -24% for data averaged over the time interval of 0-180 min post onset of hyperoxia followed by a subsequent recovery to baseline. rCBV response amplitudes were decreased by 21% in the same time interval (0-180 min). In the LGN, we neither found a significant modulation of DeltaBOLD% nor of MION response amplitude. The cerebrovascular effects of hyperoxia may, therefore, be regionally specific and cannot be explained by a deoxyhemoglobin dilution model accounting for plasma oxygenation without assuming altered neuronal activity or altered neurovascular coupling.
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Moskvin AN, Alekseeva OS, Gutsaeva DR, Khmel'nitskii AV, Sharapov OI. Effect of indomethacin on cerebral blood flow and development of oxygen convulsions. Bull Exp Biol Med 2006; 142:26-8. [PMID: 17369894 DOI: 10.1007/s10517-006-0282-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hyperbaric oxygenation modulates cerebral blood flow affecting the development of oxygen convulsions. Before hyperbaric oxygenation-induced convulsions in rats the initial decrease in blood flow gave place to hyperemia, Po(2) increased. In rats receiving cyclooxygenase inhibitor indomethacin no convulsions were observed, blood flow and Po(2)were lower than in controls. Our results indicate that indomethacin prevents hyperemia and alleviates oxygen convulsions under conditions of hyperbaric oxygenation.
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Affiliation(s)
- A N Moskvin
- Laboratory of Hyperbaric Physiology, I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg.
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Helms AK, Whelan HT, Torbey MT. Hyperbaric oxygen therapy of cerebral ischemia. Cerebrovasc Dis 2005; 20:417-26. [PMID: 16230845 DOI: 10.1159/000088979] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Accepted: 06/17/2005] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Hyperbaric oxygen (HBO) therapy of cerebral ischemia has been evaluated in a number of human and animal studies; however, there is presently no consensus on its efficacy. METHODS We present a review of animal and human studies on HBO therapy of cerebral ischemia as well as present potential mechanisms of action of HBO. RESULTS Animal studies of HBO have shown promise by reducing infarct size and improving neurologic outcome. HBO has also been shown to inhibit inflammation and apoptosis after cerebral ischemia. Early reports in humans also suggested benefit in stroke patients treated with HBO. Recent randomized, controlled human studies, however, have not shown benefit, although all were limited by small sample size. Important differences between animal and human studies suggest HBO might be more effective in stroke within the first few hours and at a pressure of 2-3 ATA. CONCLUSIONS The clinical usefulness of HBO in the treatment of cerebral ischemia is not yet certain. Attention to emerging pathophysiologic data should be taken into consideration in design of any future clinical trials of HBO in acute ischemic stroke.
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Affiliation(s)
- Ann K Helms
- Medical College of Wisconsin, Milwaukee, Wisc. 53226, USA
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